1. Field of the Invention
The present invention relates to a recording medium suitable for use in ink-jet recording and an ink-jet recording method making use of this medium.
2. Related Background Art
As recording media for ink-jet recording, there have hitherto been used recording paper as described in Japanese Patent Publication No. 3-26665, which comprises a base paper web and a coating layer provided on the base paper web and containing finely powdered silica and a water-soluble binder such as polyvinyl alcohol, glossy paper as described in Japanese Patent Publication No. 3-25352, which comprises a cast-coated paper web and a film formed on the cast-coated paper web and containing polyvinyl alcohol having a saponification degree of from 50 to 90 mole % and a crosslinking agent, and a recording sheet for OHP as described in Japanese Patent Publication No. 3-13993, which comprises a polyester film and a hydrophilic film provided on the polyester film and composed of a mixture of water-soluble polyvinyl alcohol, water-insoluble polyvinyl alcohol and a water-dispersed polyester.
With the improvement in performance of ink-jet recording apparatus, such as speeding up of recording and multi-coloring of images, recording media for ink-jet recording are also required to have improved properties. More specifically, they are required to satisfy simultaneously, for example, the following properties:
(1) having high ink absorptivity (absorbing capacity being great, and absorbing time being short);
(2) providing dots high in optical density and clear in periphery;
(3) providing dots having a substantially round shape and a smooth periphery;
(4) undergoing minimal changes in the properties even at varied temperatures and humidities and with no curling;
(5) undergoing no blocking; and
(6) being able to stably store images thereon for a long period of time without deteriorating them.
These properties are often in a relation of trade-off. It has hence been impossible to satisfy them at the same time by the conventionally known techniques. For example, the exemplified recording media of the prior art have comparable performance in dot shape and blocking resistance, but are poor in ink absorptivity. Therefore, they cause image smearing and unevenness of color strength due to running-out of ink at areas high in image density, i.e., areas on which many ink droplets have been jetted. In addition, they cause color muddiness due to mixing of colors at boundaries between different colors, particularly, in the case of color printing.
With the progress of speeding up of recording, and increasing of image density and coloring of images, reduction in image quality due to defective ink fixing has become a serious problem.
A recording sheet described in Japanese Patent Publication No. 3-29596 and having an ink-receiving layer composed principally of polyvinyl pyrrolidone is relatively good in ink absorptivity at normal temperature and humidity, but is extremely slow in drying of ink at high temperature and humidity and hence tends to cause blocking. The sheet also has a drawback that its recording surface is low in mechanical strength and hence liable to flaw.